That's assuming people even have to "get" to rank 6. FC points didn't stop accumulating when people hit rank 5. Many FCs that started within a month of release are going to hit rank 6-8 as soon as the patch is up. It's going to take more than a month because SE didn't assume that people would be buying large houses within the first few weeks. They have a set time period (unknown to us) where they think people will buy houses and that probably takes the increased gil generation of 2.1 into account. I would put any change to prices at 1-2 months at the earlier and 3 months at the latest. Hopefully, the forum posts will make them relook at the numbers that they used to set the prices (i.e. gil spread among FCs/characters), but I don't see them changing course without letting gil generation changes take effect.
I do think that the 1400+ would/should warrant a look into their initial data. I wouldn't get my hopes up that anything south of 100,000, which is impossible to get overnight (unless you are Beyonce), is going to make a sudden change. And even then, what's the change going to be? Are they going to slash a zero, or are they going to reduce the initial price by half? It's going to take time no matter what decision they choose.